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Background & objectives: The aim of this study was the effect of mucilages of Salvia macrosiphon and Plantago ovata as a prebiotic instead of fat and its effect on the sensory, microbial and survival properties of low-fat stirred yogurt probiotic.
Methods: In this study, mucilages of Salvia macrosiphon and Plantago ovata were added to the low-fat stirred yogurt in concentrations and various ratios of 0.01%, 0.04% and 0.07%, after the extraction. The effects of adding mucilage on the properties of low-fat stirred yogurt probiotic containing bifidobacterium bifidum stored at refrigerated temperature (0 to +4 °C), such as sensory, durability assessment and total probiotic bacterial count were investigated for 3 weeks. The results were analyzed using ANOVA test.
Results: The results showed that the yoghurt containing of 0.04% Salvia macrosiphon mucilage and 0.04% Plantago ovate mucilage had the highest scent, taste and sensory rating. The combination of salvia macrosiphon and Plantago ovate mucilages had a significant effect on sensory properties (p<0.05). A significant decrease was observed in the color score of yogurt samples, with increasing the percentage of the Salvia macrosiphon and Plantago ovate mucilages (p<0.05). The probiotic bacterial life of Bifidobacterium bifidum increased until the seventh day with the addition of mucilages to yogurt, and then decreased. The sample containing 0.07% mucilage of Salvia macrosiphon showed the highest amount of probiotic bacteria, but live bacterial count significantly increased with increasing of these two hydrocolloids compared to the control group (p<0.05).
Conclusion: The results of this study showed that the some doses mucilages of Plantago ovata and Salvia macrosiphon as a replacement of fat could play a significant role in keeping up the sensory properties of low fat yogurt during storage. Thses additives can improve the negative effects of reduced yogurt fat with increasing the amount of probiotic bacteria and improving oral sensation.